<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="../css/bootstrap.min.css">
    <title>Bootstrap下拉菜单效果案例</title>
</head>

<body>
    <div class="container">
        <div class="dropdown">
            <button class="btn  btn-default" id="dlabel" type="button" data-toggle="dropdown" aria-haspopup="true" aira-expanded="false">
                下拉效果
                <span class="caret"></span>
            </button>
            <ul class="dropdown-menu" role="menu" aria-labelledby="dlabel">
                <li><a href="#">1</a></li>
                <li><a href="#">2</a></li>
                <li><a href="#">3</a></li>
                <li><a href="#">4</a></li>
            </ul>
        </div>
    </div>
    <script src="../js/jquery-1.12.4.js"></script>
    <script src="../js/bootstrap.min.js"></script>
</body>

</html>